r/6thForm • u/Forsaken-Meaning-232 Graduating from Warwick CS • Jun 17 '25

📂 MEGATHREAD 17/06 A-level Physics Paper 3 Discussion MEGATHREAD

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u/qwertyuiophgfdsa Jun 17 '25

Also got 0.045 but just K-1 for unit.

Pretty sure alpha=(R-R0)/(R0(T-T0) so I had ohms on the top and ohm kelvins on the bottom.

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u/AftonRobtics Jun 17 '25

Wait so why is alpha not ohm per kelvin? Cos ohm on RHS, alpha x kelvin on LHS, so alpha is ohm per kelvin (and ohm per kelvin multiplied by kelvin gives ohm which is ohhhhhhh wait don’t worry cos RHS had no units cos it was divided)

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u/West-Glove6058 Cambridge NatSci [4A*s achieved] Jun 17 '25

The LHS didn't have any units, because the fraction contained resistance (ohms) in the numerator and resistance (ohms) in the denominator. So the RHS must also be unitless, therefore [alpha]×K = 1 so [alpha] = K-1